The present disclosure relates to a communication system and an operating method thereof, and particularly, to a communication system and an operating method, which generate system analysis information on a remote terminal unit (RTU) of a supervisory control and data acquisition (SCADA) system to control each RTU.
A SCADA system is defined as a communication system for collecting, receiving, recording, and displaying, at a remote control center (RCC), state signal data (or points) of a plurality of RTUs using an analog or digital signal on a communication path and allowing the RCC to supervise and control each of the remote RTUs.
The SCADA system is typically a system for supervising and controlling, in a centralized manner, many kinds of remote facilities such as power generation, transmission, and distribution facilities, a petrochemical plant, an iron and steel making facility, and a factory automation facility, etc.
In detail, the RCC of the SCADA system periodically obtains a state signal (or state value) at determined times, generates system analysis information (or unique algorithm) used for controlling the plurality of remote control units on the basis of the obtained state signals, and controls each of the RTUs on the basis of the generated system analysis information.
Furthermore, the RCC may receive the state signal (or value) (e.g. “open” or “close”) from each RTU and at the same time, receive signal quality information (e.g. “good” or “suspect”) including whether each state signal is normal or erroneous, generate RTU analysis information, which is analysis information on each RTU, in correspondence to the received signal quality information, and may collect the RTU analysis information on each RTU to generate system analysis information that is analysis information on the plurality of RTUs.
FIGS. 1A, 1B, and 1C illustrate an operation for receiving a state signal from each RTU to generate analysis information on each RTU on the basis thereof.
For example, as illustrated in FIG. 1A, when receiving, from a circuit breaker, a “close” (i.e. connected) state signal together with normal signal information (e.g. “good”) that includes information that the corresponding “close” state signal is normal, a control device 100 generates RTU analysis information that a “circuit breaker” is “connected” on the basis of the corresponding “close” state signal, and generates system analysis information for analyzing the plurality of RTUs including the “connected” “circuit breaker” by reflecting the RTU analysis information of “circuit breaker is connected”.
On the other hand, for example, as illustrated in FIG. 1B, when receiving, from a circuit breaker, a “close” (i.e. connected) state signal together with erroneous signal information (e.g. “suspect”) including information that the corresponding “close” state signal is erroneous, the control device 100 generates RTU analysis information that “the circuit breaker” is “open” on the basis of the “open” state signal received together at the time of receiving “good” signal quality data which is last received before receiving “suspect” signal quality data, instead of the corresponding “close” state signal, in response to the erroneous signal information (“e.g. suspect”), and reflects the RTU analysis information to generate the system analysis information for analyzing the plurality of RTUs in which the “opened circuit breaker” is included.
However, in practice, each state signal and each piece of signal quality information are not simultaneously transmitted to a control device 100 due to various causes, including delay on a communication line, and are received with a time difference as illustrated in FIG. 1C.
For example, at the time of “(1)” of FIG. 1C, the control device 100 receives a “close” state signal in a state of receiving “good” signal quality information.
Theoretically, the control device 100 is necessary to generate system analysis information on a plurality of RTUs, in which an “opened circuit breaker” is included, on the basis not of the “close” state signal, but of an “open” state signal that is a state signal received together when receiving last “good” signal quality information, in response to “suspect” signal quality information indicating that the received “close” state signal is erroneous.
In practice, though not required to use the “close” state signal, the control device 100 uses the “close” state signal in response to “good” signal quality information that is most recently received before receiving the “close” state signal, generates RTU analysis information that the “circuit breaker” is “connected” on the basis of the “close” state signal, and reflects this to generate system analysis information on the plurality of RTUs in which the “connected circuit breaker” is included.
In addition, for example, at the time of “(2)” of FIG. 1C, the control device 100 receives an “open” state signal in a state of receiving “suspect” signal quality information.
At this point, the control device 100 is necessary to generate the system analysis information on the plurality of RTUs in which an “opened circuit breaker” is included, on the basis of the “open” state signal in response to the “good” signal quality information indicating that the received “open” state signal is not erroneous but is normal.
However, in practice, the control device 100 generates system analysis information that the “circuit breaker” is “connected”, not on the basis of the “open” state signal in response to “suspect” signal quality information having already received right before receiving the “open” state signal, but on the basis of the “close” state signal in response to last “good” signal quality information before receiving the “open” state signal, and accordingly, generates the system analysis information on the plurality of RTUs in which the “connected circuit breaker” is included.
Consequently, since reception times of a state signal and signal quality information are typically different due to various causes such as a delay issue on a communication line, an error occurs and matching is degraded in generating the system analysis information on the RTUs, which outputs a state signal on the basis of a state signal.